From 20867a22495fa1cdc686b96f3d66a30bbe52a159 Mon Sep 17 00:00:00 2001
From: Dan Stahlke <dan@stahlke.org>
Date: Sun, 11 Jun 2023 21:24:49 -0700
Subject: [PATCH] chop! no longer produces empty coefficients

Test case:
    using ApproxFun
    x,y = Fun(identity, Chebyshev() * Chebyshev())
    ApproxFun.norm(0*x)
    ApproxFun.norm(zero(x))
---
 src/Fun.jl | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/Fun.jl b/src/Fun.jl
index abb676ce..a729e864 100644
--- a/src/Fun.jl
+++ b/src/Fun.jl
@@ -486,6 +486,7 @@ pad(f::Fun,n::Integer) = Fun(f.space,pad(f.coefficients,n))
 
 function chop!(sp::UnivariateSpace,cfs,tol::Real)
     n=standardchoplength(cfs,tol)
+    n=max(1,n) # empty coeffs vector causes all sorts of problems
     resize!(cfs,n)
     cfs
 end